From: "Bob May" 
To: "atmlist" 
Reply-To: "Bob May" 


Basically, the design is a double gauss design and is Rodenstock's name for
the design.  One reference refers to it as a 6 element design which will
mean that there are two triplets in the construction with the iris between
them.  Further on the basics of the design, go looking for "double
gauss" for the basic lens design.
AS to what the glass is, you will have to determine that from the way that
it refracts light and hope you guess right for each of the elements.  I'll
note that the camera lens people will go and have a glass made to a
particular design requirement which is not available on the market
otherwise so you can be trying to find a match for a glass which isn't
listed in any glass catalog and that is a head bammer! The lenses designed
for a camera also tend to have a fixed focal distance from the back
mounting surface for some rather obvious reasons.  That distance tends to
be about an inch as that is how 35mm cameras have been built.
Bob May
http://nav.to/bobmay
bobmay{at}nethere.com
NEW! http://bobmay.astronomy.net

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